Many types of weapons (such as rifles) have weapon sights that allow the weapon's user to view a target within a scene and align the weapon relative to the target, e.g., to a select a bullet impact point. A typical weapon sight includes a cross-hair reticle. The weapon sight is adjusted (“aligned”) so that cross-hairs match the desired bullet impact point for a given target distance. The typical weapon sight is configured to removably mount to a military standard rail mount (“rail”) (e.g., MIL-STD 1913) that runs along the top and/or side of the weapon (forend and barrel).
Certain types of weapon sights have night-vision capability and are referred to as “night-vision optics” or “night optics.” The night-vision optics “clip on” to the rail and may be arranged in-line with removable “day vision optics” or “day optics” used for daytime viewing, with the night-vision optics augmenting the day-vision optics for nighttime use. Some night-vision optics include an eyepiece that allows for direct viewing of the scene using just the night-vision optics so that that viewing through the day-vision optics is not required. Either way, to view a target at night, the night-vision optics must be used.
One type of night-vision optics employs passive, long-wavelength (e.g., 7.5 μm to 14 μm) thermal imaging, wherein a thermal image of the target is detected by a thermally sensitive (i.e., infrared) detector and then transmitted to a visible display within the night-vision optics. Thus, the weapon user does not view the target or scene directly, but rather views an image of the target or scene on a small display within the night-optics housing. Night-vision optics that employ thermal imaging are also called “thermal sights” or “thermal scopes.”
In nighttime applications, the weapon's user may be wearing a helmet that includes night-vision viewing equipment such as night-vision goggles. The night-vision goggles can employ thermal imaging, image intensification, or both. In order to aim the weapon at the target at night, the soldier will need to swing the night-vision goggles out of the way to gain access to the eyepiece of the weapon sight's night-vision optics. The soldier then has to hold the weapon in such a way that allows them to look through the eyepiece of the night-vision optics and then adjust the position of the weapon as needed to align the cross-hairs to a desired target impact point prior to firing the weapon. This process delays and complicates the target acquisition in life-threating situations where quick target acquisition is critical.